misc: fastrpc: Pass proper arguments to scm call

For CMA memory allocation, ownership is assigned to DSP to make it
accessible by the PD running on the DSP. With current implementation
HLOS VM is stored in the channel structure during rpmsg_probe and
this VM is passed to qcom_scm call as the source VM.

The qcom_scm call will overwrite the passed source VM with the next
VM which would cause a problem in case the scm call is again needed.
Adding a local copy of source VM whereever scm call is made to avoid
this problem.

Fixes: 0871561 ("misc: fastrpc: Add support for audiopd")
Cc: stable <stable@kernel.org>
Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
Reviewed-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240224114247.85953-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: quic-ekangupt

drivers/misc/fastrpc.c

@@ -263,7 +263,6 @@ struct fastrpc_channel_ctx {
 	int domain_id;
 	int sesscount;
 	int vmcount;
-	u64 perms;
 	struct qcom_scm_vmperm vmperms[FASTRPC_MAX_VMIDS];
 	struct rpmsg_device *rpdev;
 	struct fastrpc_session_ctx session[FASTRPC_MAX_SESSIONS];
@@ -1279,9 +1278,11 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
 
 		/* Map if we have any heap VMIDs associated with this ADSP Static Process. */
 		if (fl->cctx->vmcount) {
+			u64 src_perms = BIT(QCOM_SCM_VMID_HLOS);
+
 			err = qcom_scm_assign_mem(fl->cctx->remote_heap->phys,
 							(u64)fl->cctx->remote_heap->size,
-							&fl->cctx->perms,
+							&src_perms,
 							fl->cctx->vmperms, fl->cctx->vmcount);
 			if (err) {
 				dev_err(fl->sctx->dev, "Failed to assign memory with phys 0x%llx size 0x%llx err %d",
@@ -1915,8 +1916,10 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
 
 	/* Add memory to static PD pool, protection thru hypervisor */
 	if (req.flags == ADSP_MMAP_REMOTE_HEAP_ADDR && fl->cctx->vmcount) {
+		u64 src_perms = BIT(QCOM_SCM_VMID_HLOS);
+
 		err = qcom_scm_assign_mem(buf->phys, (u64)buf->size,
-			&fl->cctx->perms, fl->cctx->vmperms, fl->cctx->vmcount);
+			&src_perms, fl->cctx->vmperms, fl->cctx->vmcount);
 		if (err) {
 			dev_err(fl->sctx->dev, "Failed to assign memory phys 0x%llx size 0x%llx err %d",
 					buf->phys, buf->size, err);
@@ -2290,7 +2293,6 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
 
 	if (vmcount) {
 		data->vmcount = vmcount;
-		data->perms = BIT(QCOM_SCM_VMID_HLOS);
 		for (i = 0; i < data->vmcount; i++) {
 			data->vmperms[i].vmid = vmids[i];
 			data->vmperms[i].perm = QCOM_SCM_PERM_RWX;